iptables is the user-space tool for configuring firewall rules in the Linux kernel. It is actually a part of the larger netfilter framework. Perhaps because iptables is the most visible part of the netfilter framework, the framework is commonly referred to collectively as iptables. iptables has been the Linux firewall solution since the 2.4 kernel.

Cross-platform network programming made easy.

In previous articles, I've looked at a number of uses for JavaScript, on both the server and the client. I hope to continue my exploration of such systems, particularly on the client side, in the coming months.

A basic introduction to using the Python boto library to interact with AWS services and resources.

Ditch your laptop and code in the cloud—it's easier than you'd think. On September 19, 2011, I said goodbye to my trusty MacBook Pro and started developing exclusively on an iPad + Linode 512. This is the surprising story of three months spent working in the cloud.

Most people today are used to having a nice, intuitive graphical environment when they sit down to use a computer. Gone are the days of using a DOS machine or being lucky enough to have a dial-up account at 300 baud on a UNIX mainframe.

A vDSO (virtual dynamic shared object) is an alternative to the somewhat cycle-expensive system call interface that the GNU/Linux kernel provides. But, before I explain how to cook up your own vDSO, in this brief jaunt down operating system lane, I cover some basics of vDSOs, what they are and why they are useful.

Perl has been around for more than 20 years. During that time, it has received its share of both praise and criticism, and lots of misconceptions surround it. Much of this stems from long-outdated notions of what Perl used to be, but have nothing to do with what Perl actually is today.

I've realized I've missed out on a huge area of computational science—chemistry. Many packages exist for doing chemistry on your desktop. This article looks at a general tool called avogadro. It can do computations of energy and gradient values. Additionally, it can do analysis of molecular systems, interface to GAMESS and import and export from and to several file formats.

This article is a bit different from my usual column in two ways. First, it's starting with a hardware and software combo—something I've not done before. Second, the projects are linked to each other and come recommended to me by Perth LUG member, Simon Newton.

Packet capture is one of the most fundamental and powerful ways to do network analysis. You can learn virtually anything about what is going on within a network by intercepting and examining the raw data that crosses it. Modern network analysis tools are able to capture, interpret and describe this network traffic in a human-friendly manner.

There comes a time in a network or storage administrator's career when a large collection of storage volumes needs to be pooled together and distributed within a clustered or multiple client network, while maintaining high performance with little to no bottlenecks when accessing the same files. That is where Lustre comes into the picture. The Lustre

Are you looking to set up some kind of network cluster, but dealing with many different computers, all of which are nearly impossible to keep track of? What if you're in charge of a room full of computers and also of those who are using them (some of whom may be looking to slack off or run something I'll politely dub "objectionable")?

Elmer is an open-source multiphysics simulation software that has been around since 1995. It is developed by the CSC — IT Center for Science Ltd. This group is administered by the Ministry of Education, Science and Culture in Finland. With Elmer, you can model physical systems, such as fluid dynamics, electromagnetism, heat transfer and acoustics.

Imagine this: you're sitting in your local coffee shop sucking down your morning caffeine fix before heading into the office. You catch up on your work e-mail, you check Facebook and you upload that financial report to your company's FTP server. Overall, it's been a constructive morning. By the time you get to work, there's a whirlwind of chaos throughout the office.

In a compiled language, the makefile is arguably the most important part of any programming project. To compile your project, you first have to compile each source file into an object file, which in turn needs to be linked with system libraries into the final executable file. Each command can have a considerable number of arguments added in.

Scribus is a powerful tool, but its menus are poorly laid-out. While you can usually find the features you most frequently use without any trouble, others may be hidden almost anywhere. From the Extras, Script, and Windows menus to the Document Setup dialog, useful features can be positioned almost anywhere, with only the most token regard for logic.

My studio computer collection includes two custom-built desktop machines and a Hewlett-Packard G60 laptop.

Do you have a Facebook page? If you do, you are among the 600 million users who actively use the social-networking service. I'll admit I initially resisted the temptation to join Facebook. After all, I've got e-mail, instant messaging and VoIP. What do I need with yet another form of communication? Eventually, temptation got the better of me, and I gave it a try.